card
178

coral reefs

OLogy Series
place
card
178

coral reefs

OLogy Series
place

Bustling with a spectacular diversity of life, coral reefs are the rain forests of the oceans. Coral reefs are built by thousands of tiny organisms called polyps (PAH-lips), which form the outside layer of the reef. The inside layers of a reef are made of the skeletons of dead coral, some of which lived millions of years ago. Coral reefs provide shelter and food for thousands of different kinds of living organisms.

Coral Reefs Under Threat
Corals may look like solid rock, but they are actually alive and extremely fragile. They are also in great danger. One of the major threats to the reefs is pollution from sewage and industrial chemicals, which kills the animals of the reefs. Another threat is runoff, or loose dirt from construction and deforested areas, which chokes coral with sediment. Whole reefs are sometimes intentionally poisoned or blasted with dynamite to collect animals for food or aquariums. Global warming may pose one of the most direct dangers to corals. Even the slightest temperature change in the water can hurt the algae that feed the coral polyps. When these algae disappear, the corals' white calcium skeletons are exposed. This "coral bleaching" makes the reef appear ghostly white. Without these algae, the corals cannot survive. Coral reefs are an important part of the ocean ecosystem, but they are disappearing quickly. And coral reefs grow so slowly -- about an inch a year -- they could be gone in a few decades.

Which coral reef fish has a special layer of slimy mucus over its body?

the clown fish

the dogfish

the slippery fish

Are you right?

Correct!

Clown fish are coral reef dwellers in the Pacific and Indian oceans. These colorful orange fish hide among the anemones that live on the reefs. A slimy layer of mucus over the clown fish's body protects it from the anemone's stinging tentacles.

Coral reefs are created by small soft-bodied animals with hard skeletons outside of them.

Fact
or
Fiction
?

Fact

The small soft-bodied animals that create the coral reefs are called polyps. Polyps consist of a soft cup of tissue surrounded by tentacles.

At night all the reef's animals seek shelter and sleep, leaving the coral reef quiet and still until morning.

Fact
or
Fiction
?

Fiction

While some animals seek shelter at night, a variety of nocturnal animals comes out at dusk to hunt.

Made by: reef-builder corals
Habitat: clear, warm, shallow, tropical waters
Threats: human contact, pollution, blast fishing, runoff, global warming
Types: fringing reefs extending from the coastline into the sea; barrier reefs, which form offshore; and atolls, circular reefs around an island
Significance: home to about a million marine species and protect our shorelines
Status: extremely endangered

Image credits: courtesy of NOAA, Florida Keys National Marine Sanctuary.